This application claims priority from German application no. 201 14 857.9 filed on Sep. 7, 2001, under 35 USC xc2xa7119, the full disclosure of which is incorporated herein by reference.
The invention relates to an extended-nip roll press for dewatering a fibrous web.
An extended-nip roll press of this type is disclosed, for example, by DE 297 02 362 U1. According to that document, a clamping ring is provided to clamp the respective end section of the roll cover firmly, and is axially displaceably mounted on a part of the end wall which is cylindrical in some sections. The end wall is also assigned an outer ring, so that, in the circumferential area of the end wall, an annular groove that is open towards the opposite, other end wall is formed, which is bounded radially on the inside by the cylindrical part of the end wall, extending axially into the interior of the roll, and radially on the outside by an inner circumferential surface of the outer ring. The clamping ring comprises a wedge section having a conical outer circumferential surface with which the said ring engages in the annular groove. In addition, a resilient spreader ring is inserted into the annular groove, its inner circumferential surface forming a conical opposing surface that interacts with the conical outer circumferential surface of the clamping ring. On the other hand, the outer circumferential surface of the spreader ring is cylindrical and is provided with grooves in order to increase adhesion. Resilient sealing material, for example, can be inserted into these grooves. In a clamping position of the clamping ring, in which the spreader ring is widened radially because of active engagement of the wedge surfaces, the end section of the roll cover is clamped firmly in a sealing manner in a clamping gap which is formed by the cylindrical outer circumferential surface of the spreader ring and the cylindrical inner circumferential surface of the outer ring. As a result, the roll cover is pressed against the cylindrical inner surface of the outer ring.
However, it has proven to be disadvantageous that the sealing effect in the clamping position is not sufficiently good.
It is therefore an object of the invention to provide an extended-nip roll press in which attachment of the respective end section of the roll cover ensures reliable sealing. This objective is achieved by an extended-nip roll press in which the clamping engagement and the sealing engagement are functionally separated. By means of separately acting actuating devices, the clamping ring and the sealing ring are tightened separately. Individual adjustment and/or readjustment of the clamping ring and of the sealing ring are in each case possible as required. Further advantages and refinements of the invention may be gathered from the following description and the subclaims.